424 THE CRYSTAL FALLS lEOi^-BEARING DISTRICT. 



near the axial plane. East from this point similar schists and qnartzites 

 form a ridge, low and flat-topped, which extends immediately south of the 

 railway almost to the east line of section 33, and sinks gradually beneath the 

 great swamp of the eastern portion of that section. The formation notice- 

 ably disturbs the compass needles, and this fact, together with the rusty 

 appearance of the outcrops, has probably led to the sinking of the numer- 

 ous test pits by which the continuity is chiefly established. But low-lying 

 natural exposures are not lacking. 



North of the center of the NE. ^ of sec. 33 similar schists have been 

 found in two test pits. Also, parallel with the outcropping southern belt 

 and a quarter of a mile or more farther north, a faintly marked zone of 

 magnetic disturbances runs east and west through the swampy ground 

 south of Felch Mountain and probably connects the last-mentioned occur- 

 rences with the exposures of the railway cut. It therefore seems likely 

 that the low ground tln-ough the middle of sections 32 and 33 is wholly 

 occupied by an open syncline of these soft and easily disintegrating 

 rocks. 



Between the exposed southern limb of this syncline and the southern 

 Archean the lower Algonkian formations are found in the southeastern 

 portion of section 33. Actual contacts are not visible, but there are note- 

 worthy discordances in strike and dip, and especially clear proof of great 

 disturbances in the lower rocks in which the upper have not shared. In 

 the SE. J of the NE. ^ of the SW. J of sec. 33, about 200 feet thickness of 

 the Randville dolomite, striking east and west and dipping north at about 

 70°, is exposed between the Sturgeon quartzite below and the mica-schists 

 to the north. Between the dolomite and the schists is a covered interval 

 of some 40 feet. The latter also strike about east and west, but dip north 

 at 30° or less. Between a quarter and three-eighths of a mile east of this 

 locality (the interval being without outcrops) the Mansfield and Groveland 

 formations lie against the Archean gneisses with a faulted contact. They 

 have been thrown into a series of southeastward-pitching minor folds, and 

 have been intruded by a mass of diabase and also by a pegmatite dike. 

 The true strike of these formations at this locality is toward the northeast, 

 and the dip, as shown both by the direction of pitch and the order of super- 

 position, is toward the southeast. Five hundred feet north of this disturbed 

 area and directly across the strike of the lower formations therein, the 



